"That's kind of the way we're moving as the gap between the fit and the unfit grows," he told the Times.
"The teeth thing and the obesity problems are the same: they are symptoms of the same set of inferences that are being drawn.
"I think those kinds of physical characteristics - that's completely the next wave of discrimination."
The comments follow an increasing trend of celebrities and reality TV stars paying to have work done to their teeth.
The range of work includes tooth whitening using bleach, veneers and even implants in which titanium spikes are put into a person's jaw.
Experts fear that while those with money can pay to give themselves sparkling Hollywood smiles, those from poorer backgrounds can not afford to give their teeth the same treatment.
Results from the Government's Health and Social Care Information Centre also seem to back up Mr Gladwell's comments.
Statistics from the centre show one fifth of hospital admissions for dental treatments in 2011 were for patients from the most deprived 10 per cent of the population in England.
The figures also show that there were three times as many patients aged between 0 and 29 having treatment than those aged over 60 - when teeth are traditionally in worse decline.
A poll conducted last year by VisionCritical also found that people see whiter teeth as an indication of wealth.
The survey showed that people with whiter teeth were thought to earn £10,000 more on average than they actually did.
Sparkling teeth also made them look up to five years younger and improved their employment potential by 10 per cent, results showed.
Eddie Crouch from the British Dental Association also told the paper there was also a noticeable gap between middle-class teenagers able to afford to have braces fitted while those from deprived areas could not get the same treatment.
"Huge numbers of those kids that are referred to us from socially-deprived areas can't have the treatment they need because their overall standard of dental health is too poor," he said.
- Daily Mail